Purpose: The DERC Islet Metabolism Core assists investigators who currently study or have plans to study pancreatic islet cell biology, transplantation and metabolic analysis. Components: 1. Islet Purification. Processing and preparation of human and mouse islets for use in islet transplantation, genomic studies, and cell biology studies. 2. Islet Functional Analysis. Real time biological and biochemical analysis of insulin production and other functional aspects of human and mouse islets to characterize islet activity under different conditions and to assess islet preparation quality for transplantation studies. 3. Mouse Metabolic Analysis. Analysis of the metabolic status of an intact mouse including measurements of fat content, the monitoring of glucose levels in response to exogenous glucose or insulin stimulation and the analysis of oxygen consumption and/or activity. Benefits to DERC Community: These highly specialized capabilities are beyond the reach of almost ail individual laboratories. The Islet Metabolism Core consolidates these unique capabilities and enables the application of these capabilities to research studies by DERC investigators. Standardized protocols ensure reproducibility in analyses conducted on different days. Standardization also enables individual laboratories to compare outcomes. Technology Development: There is an ongoing commitment to continue the prior improvements in islet isolation and analysis. A broader work-up of islet function standard for all preps will be combined with a Core-wide database to assist investigators in making cross-study inferences. Significant improvements in the metabolic analysis of intact mice are expected to represent another major effort in the next DERC cycle.